Angiotensin-(1-7) (Ang-(1-7)) modulates the Na+-ATPase, but not the Na+,K+-ATPase activity present in pig kidney proximal tubules. The Na+-ATPase, insensitive to ouabain, but sensitive to furosemide, is stimulated by Ang-(1-7) (68% by 10-9 M), in a dose-dependent manner. This effect is due to an increase in V(max), while the apparent affinity of the enzyme for Na+ is not modified. Saralasin, a general angiotensin receptor antagonist, abolishes the stimulation, demonstrating that the Ang-(1-7) effect is mediated by receptor. The Ang-(1-7) stimulatory effect is not changed by either PD 123319, an AT2 receptor antagonist, or A779, an Ang-(1-7) receptor antagonist. On the other hand, increasing the concentration of the AT1 receptor antagonist losartan from 10-11 to 10-9 M, reverses the Ang(1-7) stimulation completely. A further increase to 10-3 M losartan reverses the Na+-ATPase activity to a level similar to that obtained with Ang-(1-7) (10-9 M) alone. The stimulatory effect of Ang-(1-7) at 10-9 M is similar to the effect of angiotensin II (AG II) alone. However, when the two peptides are both present, Na+-ATPase activity is restored to control values. These data suggest that Ang-(1-7) selectively modulates the Na+-ATPase activity present in basolateral membranes of kidney proximal tubules through a losartan-sensitive receptor. This receptor is probably different from the receptor involved in the stimulation of the Na+-ATPase activity by angiotensin II. © 2000 Elsevier Science B.V.
Caruso-Neves, C., Lara, L. S., Rangel, L. B. A., Grossi, A. L., & Lopes, A. G. (2000). Angiotensin-(1-7) modulates the ouabain-insensitive Na+-ATPase activity from basolateral membrane of the proximal tubule. Biochimica et Biophysica Acta - Biomembranes, 1467(1), 189–197. https://doi.org/10.1016/S0005-2736(00)00219-4